I've been reading more and more about the use of intensity blocks on the web, not only on Torbjorn's FasterSkier.com web site (see article on the Norwegian Women's team or "All of Them Have Trained Wrong"), but also XCSkiWorld.com ("Norwegian Coach's Seminar"), the US Cross Country Ski Team's TeamToday.com site ("V02 Training"), and even non-ski related sites like IronManLive.com ("Ironman Training and High Intensity Training: Are they compatible?"

What do all these articles have in common? They all  point to the benefit of doing blocks of high intensity effort in order to quickly increase V02max. And the earlier you build up your V02max, the more work capacity you'll have earlier in the training season. And that means being able to go that much further or faster for the same amount of effort.

Second, the different references suggest that you shouldn't  build up lactate during the session! Intervals are not done at a killer pace, but are done easy enough so you feel like to can do more at the end of the session. Too hard negates the training effect.

What do the articles disagree on? When to do intensity blocks. I've been doing an intensity session every month under Torbjorn. The US Cross Country Team is doing a block in May, July and September. 

What else is different? The duration of the block and the number of intervals during the block. Some of the programs may extend the block anywhere from a week to two weeks. One may suggest doing one interval session a day, another double workouts.  I think these difference are mainly due to the time of year or the  level of the athlete - more highly trained athletes (Olympic hopefuls) can handle more training volumes than weekend warriors like me.

V02 training was the big focus in June and July with Torbjorn. Similar to May, he recommended I do a week-long block of intensity training high in Zone 3 to the bottom of Zone 4. The training during the intensity block consisted mostly of intervals of three minutes or longer, but could include a pace session.  

There's a balance between how often you do intervals and how much time you need your body to recovery: It takes longer to build up your V02 by doing one or two interval sessions a week (last year's plan), but you have a chance to recover. Doing intensity blocks builds V02 faster, but you have to be careful to take a appropriate steps to recovery.

Overall, I've been following a very traditional training schedule: three weeks of progressively higher volume/intensity followed by and easy week.

June Highlights

• Weekly hours varied from 5.6 to 8.3. This is fewer hours than last June; I've simply had too much going on at work or home this year.
  
• I'm doing more strength sessions. Last year, it seemed every time I went to the weight room, I was sore the next couple days. This year, I'm trying to get into the weight room at least twice a week. So far, more frequent (but shorter) sessions has kept the soreness away.
  
• Core strength going well. I've put a lot of focus here, doing core and abs work every other day or so for 15-20 minutes. It's easy to do in front of the TV.
  
• I abandoned a pace session after a few minutes on June 12 - I had just returned from a business trip to Tucson the day before and was feeling very run down. I also had eaten too much at a family gathering earlier in the day. I just couldn't get my heart rate to stay in the required range. Better to rest up for another day.
  
• My June intensity block got better during the block. I noticed a pronounced slow down with each interval early in the block. Each interval was run at the same effort level and length of time, but the distance I traveled got shorter and shorter. By the end of the intensity block, I slowed down a bit by the end of the session, but it wasn't anywhere near so pronounced.
  
  I had a long discussion about that last point with Torbjorn. Clearly I was starting out each interval too fast, rollerskiing too hard, building up too much lactate early in the session. I was in the right heart rate range, but that range was was obviously too high and needed to be adjusted downward. Rule: Don't be a slave to your heart rate monitor.
  
• I had a couple of good interval days as well. A June 19 doublepole session went great! I easily got my heart rate into the right range and could have gone a little faster. On June 23, I added an extra bike interval because I felt it in me.

Overall, June was an OK month, nothing to write home about.

July Highlights

For the most part, July went quite well, certainly better than June. I put in more hours as well.

• My July time trial was slower than June by :42. I blame going too hard in June, starting out too hard in July (built up lactate too early), the high humidity/heat that day (the first warm day of the year), and tired legs from an "easy" bounding session the day before. I'm not worried.
  
• My July 17 interval session was phenomenal! I needed a very long (35 minute!) warm up to get loosened up. I did a couple short sprints, then took the first interval very easy. For each remaining interval, I built up my speed over the first minute or so. By the time I was done with my set, I felt so good that I added two more intervals! And I felt I had more in me! 
  
• A 3 hour hard distance session on June 18 was...hard, probably due to two hard days in a row. Still, felt great that I finished it in the right zone.
  
• I started doing spenst training once a week with Dan Motowski and Mike Heidinger. Spenst is max leg strength training through bounding repeats, not an aerobic exercise. Mike and Dan get me motivated - especially since they're both bounding further up the hill with each step than I am. Obviously something I need to work on...

July Intensity block went very well overall.

August?

August is more of the same - just the sessions get harder, or there are more of them. Unfortunately, I'm traveling a lot in August: I'm going to Tucson twice, up north to a Michigan Cup Committee meeting, and up north again for a family vacation. Traveling has the potential to drain you or eat away at the time you have available to train.

I've been mostly rollerskiing - only a little biking and running. I'll continue to add extra intervals to a hard workout if I'm having a good session.